President Donald Trump told his environmental chief that he intends to pull the US out of the Paris climate agreement, according to a source with knowledge of the conversation.

Trump told Environmental Protection Agency administrator Scott Pruitt, a key advocate for exiting the United Nations deal, to begin an exit plan, the source said. The strategy does not include leaving the UN Framework Convention on Climate Change (UNFCCC), which would have been a quicker, but more drastic, way to bow out of international climate dealings.

As an international treaty, the UNFCCC requires senate approval for the US to join. If the US were to withdraw from the full convention, any future reentry into the Paris agreement could be held up by a hostile upper house.

The White House still hasn’t confirmed whether Trump will yank the US out of the global pact to join Nicaragua and Syria as the only non-signatories. But multiple reports now cite White House sources

Trump will meet Wednesday afternoon with secretary of state Rex Tillerson, according to the state department’s public schedule. Tillerson has pushed for Trump to remain in the deal and his department takes lead on climate negotiations.

Many in conservative circles outside the White House are still in wait-and-see mode. Some have cautioned that Tillerson could sway Trump in their meeting, or that the slower, four-year exit process for Paris would enable a renegotiation on Trump’s terms.

Some corporations have been pushing Trump to stay in the deal as well – even fossil fuel firms, such as ExxonMobil Corp., where Tillerson was previously chief executive. Appealing to Trump’s businessman’s sensibilities, they argued the administration could secure better terms for US companies by remaining involved.

C2ES, an NGO, said it would run full page ads in Thursday’s New York Times and Wall Street Journal that feature 25 US companies urging the president to make a last minute decision to stay inside the Paris accord “for the good of the economy”. It will be the ninth time the ads have run in recent weeks.

While there’s been an internal administration struggle over whether to stay or leave Paris, few in the stay camp encouraged continued participation under the current terms.

One emerging strategy involved rejecting the non-binding 26-28% emissions cut below 2005 levels president Barack Obama promised by 2025 through a Senate vote while remaining in the broader Paris framework.

Companies in the coal mining sector, which Trump has vowed to revive, took a similar tack. Peabody Energy, for example, said on May 19 that it would “support the decision” to withdraw and that staying would require “multiple improvements”, such as the US greenhouse gas emissions target being “substantively modified”.

The National Mining Association also endorsed withdrawal, as did 22 GOP senators. That could help give Trump political cover for the move – as they represent Appalachian, midwest and west voters that backed Trump – even when large portions of corporate America have endorsed the Paris deal.

Regardless of the US plans for Paris, the nation was likely to fall well short of the goal Obama laid out in 2015 after Trump and Pruitt had taken the knife to many of the last administrations key climate initiatives.

The Trump administration allegedly wants to exit Paris to avoid potential litigation that could upend its unraveling of the Clean Power Plan, Obama-era regulations to limit carbon emissions from power plants. Reaching the US target for Paris is unlikely without that rule. Even then, additional greenhouse gas-restraining policies are necessary, and the Trump administration isn’t poised to pursue them.

“While it may be hoped that the good work being done on US emissions reductions by states, cities, businesses, and individuals will continue, the reduction of federal support for [research and development] on clean and efficient energy, the abandonment or weakening of federal regulations aimed at reducing emissions, and the (continuing) refusal to put a price on carbon emissions, despite the recommendations of leading Republicans from past administrations, will make it extremely difficult to meet the emissions-reduction targets to which the United States committed itself in Paris,” John Holdren, Obama’s former science and technology adviser and currently a professor at Harvard University, said in an email.

US lawmakers, academics and others reacted to reports under the impression that Trump’s decision to leave Paris was final and imminent.

“Disappointed by early reports that the US will join Syria and Nicaragua as the only countries not party to the #ParisAgreement,” tweeted Florida Republican Rep. Carlos Curbelo, who co-chairs the House Climate Solutions Caucus that includes 20 GOP and 20 Democratic lawmakers. He added, “No matter @POTUS’ decision on #ParisAccord I’ll continue working with Rs & Ds in Congress to promote clean energy & sound enviro policies.”

Richard N. Haass, a former state department official under President George W. Bush who is now president of the Council on Foreign Relations, said on Twitter: “taking US out of Paris pact unwarranted-we set our own ceilings, little effect on eco growth-& unwise as signals US no longer ready to lead”.